Basis of Presentation and Significant Accounting Policies - Components of Crude Oil Inventories Volumes (Detail)	Sep. 30, 2014 bbl	Dec. 31, 2013 bbl
Accounting Policies [Abstract]
Crude oil line fill and tank requirements	941,000	370,000
Temporarily stored crude oil	196,000	344,000
Total	1,137,000	714,000